Scan Troubleshooting

This page documents known scan-related errors and the steps to resolve them. Each section describes the error, its cause, and a step-by-step resolution.

Connection Interrupted During a Scan

When running a scan, you may see an error like the following for one or more containers:

The connection to your source datastore was interrupted while reading '<CONTAINER_NAME>'.

Cause: The source database ended a connection that was already open while Qualytics was reading data. This is usually not a data-quality problem and not a problem with your connection settings. Common triggers include:

• A maintenance or load window on the source that restarts services or ends long-running sessions.
• A database administrator or server policy that ends long-running read sessions.
• A network device (firewall, load balancer, or VPN) that resets long-lived connections.

Because the interruption is temporary, re-running the same scan usually succeeds. Scans that read very large tables, or that overlap a scheduled data load on the source, are the most likely to be affected. This is also why the same scan can take noticeably longer on one run than another.

Resolution:

1. Re-run the scan. Qualytics automatically retries a read that is interrupted this way, so a fresh run often completes on its own.
2. If the failures keep happening, schedule scans to run outside the source's maintenance or data-load window. See Schedule Options.
3. For large, frequently updated tables, use an Incremental scan so each run reads only new or changed records and spends less time connected to the source.
4. If the source is heavily loaded during your scan window, consider pointing the datastore at a read replica or reporting copy of the database.

Unloadable Container Error

When running a scan, a profile, or a quality check validation, you may encounter the following error for specific containers:

Container '<CONTAINER_NAME>' is marked as Unloadable. No attempt was made to load the container due to multiple consecutive failures in prior operations.

Cause: This error occurs when a container has failed in 3 consecutive scan or profile operations. The count combines scans and profiles chronologically. To prevent repeated failed attempts and optimize performance, Qualytics marks the container as "Unloadable" and skips it in subsequent operations. Any later attempt to use the container (running another scan or profile, or validating a quality check against it) surfaces the same error until the status is cleared.

Resolution: The steps to clear the Unloadable status depend on the container type.

Tables, views, and file patterns

These containers are discovered from the datastore catalog, so a successful Sync operation resets their status.

1. Navigate to your source datastore.
2. Run a Sync Operation on the datastore.
3. Once the sync operation completes successfully, the container status is reset.
4. Re-run the operation that surfaced the error (scan, profile, or check validation). The previously unloadable container should now process normally.

Computed assets (Computed Tables, Computed Files, Computed Joins)

Computed assets are defined inside Qualytics, not discovered from the datastore catalog, so a Sync operation does not reset their status. Instead, you need to force an edit on the asset and re-save its definition. Re-saving runs the validation against the datastore again and clears the Unloadable status.

1. Navigate to the source datastore where the computed asset lives.
2. Open the computed asset and click Edit to force the asset into edit mode.
3. Review the SQL query or transformation and apply any change needed to make it work again (for example, after a renamed source column, a removed table, or a schema change in an upstream container). If the definition still looks correct, you can re-save it as-is to force Qualytics to re-evaluate it.
4. Click Validate to confirm the query runs successfully against the datastore.
5. Click Save. Saving a successfully validated definition clears the Unloadable status, and the asset becomes available again for scans, profiles, and check validations.

For details on editing computed assets, see Computed Tables, Computed Files, and Computed Joins.